The present invention relates to power management in an information processing apparatus, and more particularly, to an information processing apparatus that automatically detects that a portable information processing apparatus is in a state of laptop use to perform power management thereto, a power management method of the information processing apparatus, and program for executing the above.
In recent years, high-performance components such as a central processing unit (CPU), a hard disk, a CD-RW and the like are incorporated in a notebook type information processing apparatus. For this reason, a heating value of the notebook type information processing apparatus tends to increase more and more. The generated amount of heat is released to the outside of a housing through a cooling mechanism, such as a fan, a heat sink or the like in order to suppress a housing temperature to be less than or equal to a predetermined temperature. Nonetheless, in a portable information processing apparatus such as, in particular, a notebook type personal computer for example, since a bottom of the housing does not have an enough thermal diffusion efficiency, it tends to get hotter compared with other portions.
Moreover, as the downsizing of the information processing apparatus has been achieved, the information processing apparatus has been increasingly brought with a user and used on a user's lap in many cases. When the user uses the information processing apparatus on the lap, if the CPU or the like is operated at full power, the bottom of the housing gets hotter, and it is assumed, in some cases, to provide discomfort to the user. Accordingly, it has been required to detect in what kind of environment the information processing apparatus is used by the user and to perform the power management processing based on the result.
Until now, various power management methods have been proposed. For example, in JP11-296128A (Patent Document 1), there is provided a disclosure of a technique by which a trigger for reducing a frequency of a video clock is detected in association with a kind of an application, the frequency of the video clock is subsequently reduced to a predetermined frequency during a vertical retrace line of the display unit using the video clock, and the frequency is kept until the user changes the application.
Moreover, in JP2003-345465A (Patent Document 2), there is provided a disclosure of a technique by which a sensor arranged at a bottom of a laptop computer detects a temperature at the bottom of the housing of the laptop computer, and a signal for starting an auxiliary cooling action for reducing the temperature of the housing is generated. According to this technique, a temperature at a position of the worst thermal diffusion efficiency caused by a touch with the laptop computer is detected to adjust the power consumption of the laptop computer. According to this technique, however, the power consumption control is not initiated until the temperature is increased, thereby leading the user to receive a thermal stimulation from the bottom at that moment.
Furthermore, as a technique of feeding back a detected vibration result to a control of the information processing apparatus, for example in JP2004-146036A (Patent Document 3), there is provided a disclosure of a computer system for processing of evacuating a magnetic head by employing a sensor for detecting environment changes of a magnetic disk unit to predict a physical shock with reference to past records.
These systems are configured to reduce the temperature of the housing by either reducing the video clock rate according to a type of software product currently used, or directly measuring the temperature of the bottom of the housing to initiate the auxiliary cooling action. There is also provided a disclosure of a technique for detecting a vibration provided to the computer system to execute the processing based on the past records. Moreover, a method and a system for controlling the temperature are disclosed in JP2002-163038A (Patent Document 4). Also in this case, the computer is controlled by detecting the temperature, and a relative relationship between the user and the information processing apparatus is not taken into consideration. There is provided a disclosure of the techniques for reducing the temperature of the housing and detecting the vibration to be used for the control, but there is not provided a disclosure of all the techniques for determining the relative relationship between the information processing apparatus and the user from an ergonomic viewpoint, and performing a power management in response to the environments and arrangements under which the user uses the information processing apparatus.
[Patent Document 1] Japanese Unexamined Patent Publication (Kokai) No. H11-296128
[Patent Document 2] Japanese Unexamined Patent Publication (Kokai) No. 2003-345465
[Patent Document 3] Japanese Unexamined Patent Publication (Kokai) No. 2004-146036
[Patent Document 4] Japanese Unexamined Patent Publication (Kokai) No. 2002-163038